Interpretive Summary: Orchardgrass (Dactylis glomerata L.) has two commodities, forage and seed, that are produced in contrasting environments. Seed is produced in the Willamette Valley of Oregon; forage is produced throughout much of the northern USA. Simultaneous improvement of both commodities in a single breeding program is highly problematic due to geographic separation of these environments. We showed that even the most comprehensive efforts to utilize sophisticated multi-location selection protocols to improve seed yield were less efficient than selection within the target population of environments. We also showed that selection for seed yield within the target population of environments did not result in improvements in forage yield. The most efficient simultaneous selection for forage and seed traits will require use of both types of environments. Selection for forage yield should be done in forage-production environments, while selection for seed production should be done in Oregon. This work provides a blueprint for orchardgrass breeders seeking to develop germplasm with improved forage and seed yield, demonstrating the value of tandem or simultaneous selection in both forage and seed production environments.

Technical Abstract:
Simultaneous improvement of forage traits and seed yield in orchardgrass (Dactylis glomerata L.) has been problematic because of geographic separation of forage and seed production locations. Previous work has shown that a complex multi-location selection program in forage production environments can increase forage yield as well as seed yield in Oregon. The objective of this experiment was to compare target-environment (TE) and non-target-environment (NTE) selection approaches for increasing seed yield of orchardgrass in Oregon. Two cycles of recurrent phenotypic selection for panicle seed mass (PSM) and agronomic traits were conducted on four populations using four eastern USA locations (NTE) and one Oregon location (TE). Seed yield was increased in four orchardgrass populations by TE selection, averaging 5.1 % cycle-1, but was improved by NTE selection in only one of four populations. Conversely, TE selection for PSM and agronomic traits resulted in no changes to forage yield in the eastern USA and Canada, while NTE selection for PSM and agronomic traits increased forage yield in two of four populations, confirming results of a previous study. It appears that the most efficient system for simultaneously improving forage and seed traits of orchardgrass would be to practice selection for forage traits in forage production environments and seed traits in seed production environments, using sufficiently large populations to allow multi-trait selection.